Weak spots and more villainess

How serious would it be if I had a weakness for one of my pupils? Cause I do, I seriously do. He gives me the cheek, I tell him off, he throws me a disarming grin, and I let it pass. I caught myself avoiding him when Vile Year 9 made me give them a class detention. I suppose it would be really bad if he was a problem kid. But he’s not. He actually works. And wants to learn. Which made me feel horrid when I had to enforce his detention along with all others. Which doesn’t make it more sane.
Speaking of which, what do you think about detentions? I tend to follow school policy and give them when deserved. But one other PGCE trainee told me all puffed-up that she has never given one in her life cause she doesn’t believe in detentions. And anyway, she never was in a situation where she would have to give one (read: you can’t control your students, I can, or even: guess kids don’t react well to you, what a lousy teacher). I don’t know, I’ve just remembered that detention I gave to a really disruptive kid in my first school, and it was an opportunity for us to talk, work things out and make them better. But how can you do that when you have dozens in detention every afternoon? I do. Vile Year 9 and now also Vile Year 8. I counted. Out of 15 lessons I teach in a week, I’m definitely not looking forward to at least 7. And there’s no telling if one of my Year 7 groups won’t turn out to be vile too. It all makes me so tired…